1. Field of the Invention
The present invention relates to a system for performing inter-device direct communication. More particularly, the present invention relates to a method and an apparatus for a broadcast in a system performing inter-device direct communication.
2. Description of the Related Art
As a communication apparatus and a communication system evolve, there is an increasing desire by users for a service through which the users may easily obtain and share information at any time. Recently, with the introduction of a smart phone and a tablet Personal Computer (PC), an environment is provided that allows a user to obtain and share information via a wireless communication system. However, the information obtaining and sharing method of the related art is applicable to only a wireless communication system where an infrastructure has been established, and cannot efficiently provide real-time information due to the complexity of the wireless communication system or a time delay.
Accordingly, an inter-device direct communication service (referred to as D2D) for configuring a communication link between devices by directly sharing information between devices in an environment where a communication infrastructure has not been established emerges.
Devices supporting an inter-device direct communication service obtain synchronization with a neighbor device, and then perform a retrieve process with the neighbor device via a predetermined resource at a predetermined time point in order to obtain information about the neighbor device. Here, device information includes identity information of a relevant device, an interest field, and application program information. After that, each device generates a Connection IDentifier (CID) in order to connect to devices with which it desires to directly communicate based on the obtained neighbor device information, and performs direct communication based on the generated CID.
As described above, the inter-device direct communication scheme of the related art is a communication scheme suitable for one-to-one (1:1) unicast communication for transmitting/receiving a signal to/from another device, and is not suitable for (1:N)-type broadcast where one device simultaneously transmits a signal to a plurality of devices. That is, in a case of broadcasting according to the related art, it is inefficient for one device to generate a CID for each of a plurality of devices in order for one device to transmit/receive a signal to/from the plurality of devices. Furthermore, since a limited number of CIDs should be divided into a unicast CID and a broadcast CID, it is not efficient in an aspect of operating CIDs. More particularly, in a case of separately operating a CID for broadcast, it is not easy to determine the number of broadcast CIDs in advance. Also, in a case of variably changing the number of broadcast CIDs, a separate process for a variable CID is required. Accordingly, in the related art, overhead increases and inefficiency occurs.
Therefore, a broadcast communication scheme where one device simultaneously transmits a signal to a plurality of devices in an inter-device direct communication system should to be provided.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present invention.